In general, in the internal-combustion engine, the cylinder head is assembled to the upper portion of the cylinder block and is fastened by a plurality of fastening bolts, and a plurality of combustion chambers are arranged in a linear fashion. An intake port and an exhaust port are formed for each of the combustion chambers, respectively, so as to oppose to each other, in which an intake path communicates with each intake port, on the other hand, an exhaust path communicates with each exhaust port, and they may be opened and closed by an intake valve and an exhaust valve, respectively. Also, an injector for injecting fuel into each intake path or each combustion chamber is mounted, and an ignition plug for igniting mixed air in the combustion chamber is mounted. An intake tube is connected to each intake path through an intake manifold, on the other hand, an exhaust tube is connected to each exhaust path through an exhaust manifold.
Therefore, when opening the intake valve, air is inhaled from the intake path through the intake port to the combustion chamber, and the fuel is injected from the injector to the intake path or the combustion chamber, then in the combustion chamber, mixed air of air and fuel is compressed by rising of a piston and high-pressure mixed air is introduced into the ignition plug and is ignited to explode, so that driving force can be obtained, and when opening the exhaust valve, the exhaust gas after combustion is discharged through the exhaust port to the exhaust path.
As such an internal-combustion engine, there is one, which is made smaller by integrally providing an exhaust assembling section in the cylinder head, without fixing a separate exhaust manifold to the cylinder head. The conventional cylinder head with the exhaust assembling section integrally formed is configured such that the exhaust ports communicate with a plurality of combustion chambers, the exhaust ports are assembled to open on a side surface, the exhaust tube is connected to the assembling section, and a turbo supercharger is mounted on the exhaust tube.
Meanwhile, as the cylinder head of the above-described conventional internal-combustion engine, there is one disclosed in the following patent document 1, for example.    Patent Document 1: JP-A-01-182560